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2 years ago

Solve x^2 – 3x = 18 by factoring.

Mathematics

1 answer:

Ganezh [65]2 years ago

6 0

Answer:

Step-by-step explanation:

x²-6x+3x-18=0

x(x-6)+3(x-6)=0

(x+3)(x-6)=0

x=-3 or 6

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A physical therapist wants to determine the difference in the proportion of men and women who participate in regular sustained p

Alekssandra [29.7K]

Using the z-distribution and the formula for the margin of error, it is found that:

a) A sample size of 54 is needed.

b) A sample size of 752 is needed.

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which z is the z-score that has a p-value of $\frac{1+\alpha}{2}$ .

The margin of error is of:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

90% confidence level, hence $\alpha = 0.9$ , z is the value of Z that has a p-value of $\frac{1+0.9}{2} = 0.95$ , so $z = 1.645$ .

Item a:

The estimate is $\pi = 0.213 - 0.195 = 0.018$ .

The sample size is n for which M = 0.03, hence:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.03 = 1.645\sqrt{\frac{0.018(0.982)}{n}}$

$0.03\sqrt{n} = 1.645\sqrt{0.018(0.982)}$

$\sqrt{n} = \frac{1.645\sqrt{0.018(0.982)}}{0.03}$

$(\sqrt{n})^2 = \left(\frac{1.645\sqrt{0.018(0.982)}}{0.03}\right)^2$

$n = 53.1$

Rounding up, a sample size of 54 is needed.

Item b:

No prior estimate, hence $\pi = 0.05$

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.03 = 1.645\sqrt{\frac{0.5(0.5)}{n}}$

$0.03\sqrt{n} = 1.645\sqrt{0.5(0.5)}$

$\sqrt{n} = \frac{1.645\sqrt{0.5(0.5)}}{0.03}$

$(\sqrt{n})^2 = \left(\frac{1.645\sqrt{0.5(0.5)}}{0.03}\right)^2$

$n = 751.7$

Rounding up, a sample of 752 should be taken.

A similar problem is given at brainly.com/question/25694087

5 0

2 years ago

5.3.PS-/ Simplify the expression. - -2.8f + 0.8f – 16 - 9

bezimeni [28]

=-2f-25 is your answer

8 0

2 years ago

Ez pls help i will give extra points

My name is Ann [436]

Answer:

25.4

Step-by-step explanation:

1/3 ( 2.55+.75) +3* 8.1

Using pemdas, parentheses first

1/3 ( 3.3) +3* 8.1

Then multiply

1.1 + 24.3

Then add

25.4

7 0

2 years ago

a coin is flipped 5 times. we then observe the number of times a coin lands on heads. what is the compliment of the event "at le

tamaranim1 [39]

If at least one has to be heads then it would be 1/5

3 0

2 years ago

What is the degree measure of z?. A) 29° B) 39° C) 41° D) 68°

Lunna [17]

Answer:

D) 68°

Step-by-step explanation:

The exterior angle of a triangle is equal to the sum of the opposite interior angles

z = 39+29

z =68

8 0

3 years ago

Read 2 more answers